P0172
2GR-FSE ENGINE CONTROL SYSTEM: SFI SYSTEM: P0171, P0172, P0174, P0175, P1170, P117B: System Too Lean (Bank 1)
DTC P0171 - System Too Lean (Bank 1)
DTC P0172 - System Too Rich (Bank 1)
DTC P0174 - System Too Lean (Bank 2)
DTC P0175 - System Too Rich (Bank 2)
DTC P1170 - Port Injector Fuel Performance
DTC P117B - Direct Injector Fuel Performance
DESCRIPTION
The fuel trim is related to the feedback compensation value, not to the basic injection time. The fuel trim consists of both the short-term and the long-term fuel trims.
The short-term fuel trim is fuel compensation that is used to constantly maintain the stoichiometric air fuel ratio. The signal from the Air-Fuel ratio (A/F) sensor indicates whether the air-fuel ratio is rich or lean compared to the stoichiometric ratio. This triggers a reduction in the fuel injection volume if the air fuel ratio is rich and an increase in the fuel injection volume if it is lean.
Factors such as individual engine differences, wear over time and changes in operating environment cause short-term fuel trim to vary from the ideal theoretical value. The long-term fuel trim controls overall fuel compensation. The long-term fuel trim compensates for long term deviations of the fuel trim from the ideal theoretical value. These long term deviations result from the corrections made by the short-term fuel trim.
If both the short-term fuel and long-term fuel trims are lean or rich beyond predetermined values, it is interpreted as a malfunction, and the ECM illuminates the MIL and sets a DTC.
HINT
- When DTC P0171 or P0174 is set, the actual air fuel ratio is on the lean side. When DTC P0172 or P0175 is set, the actual air fuel ratio is on the rich side.
- If the vehicle runs out of fuel, the air fuel ratio is lean and DTC P0171 or P0174 may be set. The MIL is then illuminated.
- When the total of the short-term and long-term fuel trim values is within the malfunction threshold (and the engine coolant temperature is more than 75°C [167°F]), the system is functioning normally.
- When DTC P1170 or P117B is output, it may not be possible to precisely determine whether the port injection or the direct injection is malfunctioning, depending on the conditions. In this case, perform an Active Test (control the injection way) to determine which injection system is malfunctioning.
MONITOR DESCRIPTION
Under closed-loop fuel control, fuel injection volumes that deviate from those estimated by the ECM cause changes in the long-term fuel trim compensation value. The long-term fuel trim is adjusted when there are persistent deviations in the short-term fuel trim values. Deviations from the ECM's estimated fuel injection volumes also affect the average fuel trim learning value, which is a combination of the average short-term fuel trim (fuel feedback compensation value) and the average long-term fuel trim (learning value of the air-fuel ratio). If the average fuel trim learning value exceeds the malfunction threshold, the ECM interprets this as a fault in the fuel system and sets a DTC.
- Example:
- If the average fuel trim learning value is +35% or more or -35% or less, the ECM interprets this as a fuel system malfunction.
MONITOR STRATEGY
TYPICAL ENABLING CONDITIONS
TYPICAL MALFUNCTION THRESHOLDS
Fuel trim Lean / Rich (P0171, P0172, P0174, P0175)
Fuel trim (port injection, P1170)
Fuel trim (direct injection, P117B)
CONFIRMATION DRIVING PATTERN
1. Connect the Techstream to the DLC3.
2. Turn the engine switch on (IG) and turn the Techstream on.
3. Clear DTCs (even if no DTCs are stored, perform the clear DTC operation).
4. Turn the engine switch off and wait for at least 30 seconds.
5. Turn the engine switch on (IG) and turn the Techstream on [A].
6. Start the engine and warm it up until the engine coolant temperature is 75°C (167°F) or higher with all the accessories switched off [B].
7. With the engine warmed up, idle the engine for 2 minutes or more [C].
8. Drive the vehicle at a speed between 60 and 135 km/h (38 and 85 mph) for 5 minutes or more [D].
CAUTION:
When performing the confirmation driving pattern, obey all speed limits and traffic laws.
9. Enter the following menus: Powertrain / Engine and ECT / Trouble Codes [E].
10. Read the pending DTCs.
HINT
If a pending DTC is output, the system is malfunctioning.
11. If no pending DTC is output, perform a universal trip and check for permanent DTCs Reading and Clearing Diagnostic Trouble Codes.
HINT
- If a permanent DTC is output, the system is malfunctioning.
- If no permanent DTC is output, the system is normal.
WIRING DIAGRAM
Refer to DTC P2195 P2195.
INSPECTION PROCEDURE
HINT
The Techstream only:
Malfunctioning areas can be identified by performing the Control the Injection Volume for A/F Sensor function provided in the Active Test. The Control the Injection Volume for A/F Sensor function can help to determine whether the Air-Fuel Ratio (A/F) sensor, Heated Oxygen (HO2) sensor and other potential trouble areas are malfunctioning.
The following instructions describe how to conduct the Control the Injection Volume for A/F Sensor operation using the Techstream.
(a) Connect the Techstream to the DLC3.
(b) Start the engine and turn the Techstream on.
(c) Warm up the engine at an engine speed of 2500 rpm for approximately 90 seconds.
(d) Enter the following menus: Powertrain / Engine / Active Test / Control the Injection Volume for A/F Sensor.
(e) Perform the Control the Injection Volume for A/F Sensor operation with the engine in an idling condition (press the RIGHT or LEFT button to change the fuel injection volume.)
(f) Monitor the output voltages of the A/F and HO2 sensors (AFS Voltage B1S1 and O2S B1S2 or AFS Voltage B2S1 and O2S B2S2) displayed on the Techstream.
HINT
- The Control the Injection Volume for A/F Sensor operation lowers the fuel injection volume by 12.5% or increases the injection volume by 25%.
- Each sensor reacts in accordance with increases and decreases in the fuel injection volume.
NOTICE:
The Air-Fuel Ratio (A/F) sensor has an output delay of a few seconds and the Heated Oxygen (HO2) sensor has a maximum output delay of approximately 20 seconds.
- Following the Control the Injection Volume for A/F Sensor procedure enables technicians to check and graph the voltage outputs of both the A/F and HO2 sensors.
- To display the graph, selecting the following menu items on the Techstream: Powertrain / Engine / Active Test / Control the Injection Volume for A/F Sensor / A/F B1S1 and O2S B1S2 or A/F B2S1 and O2S B2S2.
HINT
- Read freeze frame data using the Techstream. The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. When troubleshooting, freeze frame data can be helpful in determining whether the vehicle was running or stopped, whether the engine was warmed up or not, whether the air fuel ratio was lean or rich, as well as other data recorded at the time of a malfunction Freeze Frame Data.
- A low A/F sensor voltage could be caused by a rich air fuel mixture. Check for conditions that would cause the engine to run rich.
- A high A/F sensor voltage could be caused by a lean air fuel mixture. Check for conditions that would cause the engine to run lean.
- Bank 1 refers to the bank that includes the No. 1 cylinder*.
*: The No. 1 cylinder is the cylinder which is farthest from the transmission.
- Bank 2 refers to the bank that does not include the No. 1 cylinder.
- Sensor 1 refers to the sensor closest to the engine assembly.
- Sensor 2 refers to the sensor farthest away from the engine assembly.
PROCEDURE
1. CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO P0171, P0172, P0174, P0175, P1170 OR P117B)
(a) Connect the Techstream to the DLC3.
(b) Turn the engine switch on (IG) and turn the Techstream on.
(c) Enter the following menus: Powertrain / Engine / Trouble Codes.
(d) Read the DTCs.
Result:
HINT
If any DTCs other than P0171, P0172, P0174, P0175, P1170 and P117B are output, troubleshoot those DTCs first.
B -- GO TO DTC CHART SFI System
A -- Continue to next step.
2. PERFORM SYSTEM CHECK (D-4S TEST)
(a) Connect the Techstream to the DLC3.
(b) Start the engine and turn the Techstream on.
(c) Enter the following menus: Powertrain / Engine / Active Test / Control the Injection Way / Port.
(d) Read the value Short FT #1 and Long FT #1 and/or Short FT #2 and Long FT #2.
OK:
Short FT #1 (#2) + Long FT #1 (#2) = Between -19% and +19%
(e) Enter the following menus: Powertrain / Engine / Active Test / Control the Injection Way / Direct.
(f) Read the value Short FT #1 and Long FT #1 and/or Short FT #2 and Long FT #2.
OK:
Short FT #1 (#2) + Long FT #1 (#2) = Between -19% and +19%
Result:
D -- CHECK PCV HOSE
C -- CHECK FUEL INJECTOR FOR PORT INJECTION
B -- CHECK FUEL PRESSURE SENSOR
A -- Continue to next step.
3. CHECK IF VEHICLE HAS RUN OUT OF FUEL IN PAST
(a) Has the vehicle run out of fuel in the past?
NO -- CHECK FOR INTERMITTENT PROBLEMS Check For Intermittent Problems
YES -- DTC CAUSED BY RUNNING OUT OF FUEL
4. CHECK PCV HOSE
(a) Check the PCV hose connections Testing and Inspection.
OK:
PCV hose is connected correctly and is not damaged.
NG -- REPAIR OR REPLACE PCV HOSE
OK -- Continue to next step.
5. CHECK AIR INDUCTION SYSTEM
(a) Check the air induction system for vacuum leakage.
OK:
No leakage from air induction system.
NG -- REPAIR OR REPLACE AIR INDUCTION SYSTEM
OK -- Continue to next step.
6. PERFORM ACTIVE TEST USING TECHSTREAM (CONTROL THE INJECTION VOLUME)
(a) Connect the Techstream to the DLC3.
(b) Start the engine and turn the Techstream on.
(c) Warm up the engine and run the engine at an engine speed of 2500 rpm for approximately 90 seconds.
(d) Enter the following menus: Powertrain / Engine / Active Test / Control the Injection Volume.
(e) Perform the Control the Injection Volume operation with the engine in an idling.
(f) Monitor the output voltages of the A/F and HO2 sensors (AFS Voltage B1S1 and O2S B1S2 or AFS Voltage B2S1 and O2S B2S2) displayed on the Techstream.
HINT
- Change the fuel injection volume with in the range of - 12.0% to 12%. The injection volume can be changed in fine gradations.
- The air fuel ratio sensor has an output delay of a few seconds and the heated oxygen sensor has a maximum output delay of approximately 20 seconds.
Result:
Lean:
During the Control the Injection Volume Active Test, the air fuel ratio sensor output voltage (AFS Voltage) is consistently higher than 3.4 V, and the heated oxygen sensor output voltage (O2S) is consistently below 0.4 V.
Rich:
During the Control the Injection Volume Active Test, the AFS Voltage is consistently below 3.1 V, and the O2S is consistently higher than 0.55 V.
Lean/Rich:
During the Control the Injection Volume Active Test, the output voltage of the heated oxygen sensor alternates correctly.
B -- INSPECT AIR FUEL RATIO SENSOR (HEATER RESISTANCE)
A -- Continue to next step.
7. READ VALUE USING TECHSTREAM (COOLANT TEMP)
(a) Connect the Techstream to the DLC3.
(b) Turn the engine switch on (IG) and turn the Techstream on.
(c) Enter the following menus: Powertrain / Engine / Data List / Coolant Temp.
(d) Read the Coolant Temp twice, when the engine is both cold and warmed up.
Standard:
With cold engine
Same as ambient air temperature.
With warm engine
Between 75 and 100°C (167 and 212°F)
NG -- REPLACE ENGINE COOLANT TEMPERATURE SENSOR Removal
OK -- Continue to next step.
8. READ VALUE USING TECHSTREAM (MAF)
(a) Connect the Techstream to the DLC3.
(b) Turn the engine switch on (IG).
(c) Turn the Techstream on.
(d) Start the engine
(e) Enter the following menus: Powertrain / Engine / Data List / All Data / MAF and Coolant Temp.
(f) Allow the engine to idle until Coolant Temp reaches 75°C (167°F) or higher.
(g) Read MAF with the engine speed at 3000 rpm.
Standard:
Between 13.0 gm/sec and 14.0 gm/sec (shift lever: N, A/C: Off).
NG -- CHECK HARNESS AND CONNECTOR
OK -- Continue to next step.
9. CHECK FUEL PRESSURE (LOW PRESSURE)
(a) Check the fuel pressure Testing and Inspection.
NG -- CHECK FUEL PUMP OPERATION
OK -- Continue to next step.
10. CHECK FOR EXHAUST GAS LEAK
(a) Check for exhaust gas leaks.
OK:
No gas leakage.
NG -- REPAIR OR REPLACE EXHAUST SYSTEM
OK -- Continue to next step.
11. CHECK SPARKS AND IGNITION
(a) Perform a spark test Testing and Inspection.
NG -- REPAIR OR REPLACE IGNITION SYSTEM
OK -- PERFORM CONFIRMATION DRIVING PATTERN
12. INSPECT AIR FUEL RATIO SENSOR (HEATER RESISTANCE) P0031
NG -- REPLACE AIR FUEL RATIO SENSOR Removal
OK -- Continue to next step.
13. CHECK TERMINAL VOLTAGE (+B OF A/F SENSOR) P0031
NG -- INSPECT A/F RELAY
OK -- Continue to next step.
14. CHECK HARNESS AND CONNECTOR (A/F SENSOR - ECM) P2237
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
15. REPLACE AIR FUEL RATIO SENSOR
(a) Replace the A/F sensor Removal.
NEXT -- Continue to next step.
16. PERFORM CONFIRMATION DRIVING PATTERN
(a) Connect the Techstream to the DLC3.
(b) Turn the engine switch on (IG) and turn the Techstream on.
(c) Clear the DTCs Reading and Clearing Diagnostic Trouble Codes.
(d) Drive the vehicle according to the Confirmation Driving Pattern.
NEXT -- Continue to next step.
17. CHECK WHETHER DTC OUTPUT RECURS (DTC P0171, P0172, P0174, P0175, P1170 OR P117B)
(a) Enter the following menus: Powertrain / Engine / Trouble Codes / Pending.
(b) Read the pending DTCs.
Result:
B -- END
A -- Continue to next step.
18. CHECK HARNESS AND CONNECTOR
(a) Check the connection and terminal contact pressure of connectors and wire harness between the mass air flow meter sub-assembly and ECM Electronic Circuit Inspection Procedure.
HINT
Repair any problems.
NEXT -- Continue to next step.
19. PERFORM CONFIRMATION DRIVING PATTERN
(a) Connect the Techstream to the DLC3.
(b) Turn the engine switch on (IG) and turn the Techstream on.
(c) Clear the DTCs Reading and Clearing Diagnostic Trouble Codes.
(d) Drive the vehicle according to the Confirmation Driving Pattern.
NEXT -- Continue to next step.
20. CHECK WHETHER DTC OUTPUT RECURS (DTC P0171, P0172, P0174, P0175, P1170 AND/OR P117B)
(a) Enter the following menus: Powertrain / Engine / Trouble Codes / Pending.
(b) Read the pending DTCs.
Result:
B -- END
A -- Continue to next step.
21. CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - ECM)
(a) Disconnect the E83 MAF meter connector.
(b) Disconnect the E6 ECM connector.
(c) Measure the resistance according to the value(s) in the table below.
Standard resistance (Check for open):
Standard resistance (Check for short):
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
22. REPLACE MASS AIR FLOW METER
(a) Replace the mass air flow meter Removal.
HINT
If the result of the inspection performed in step 8 indicated no problem, proceed to the next step without replacing the mass air floe meter.
NEXT -- Continue to next step.
23. PERFORM CONFIRMATION DRIVING PATTERN
(a) Connect the Techstream to the DLC3.
(b) Turn the engine switch on (IG) and turn the Techstream on.
(c) Clear the DTCs Reading and Clearing Diagnostic Trouble Codes.
(d) Drive the vehicle according to the Confirmation Driving Pattern.
NEXT -- Continue to next step.
24. CHECK WHETHER DTC OUTPUT RECURS (DTC P0171, P0172, P0174, P0175, P1170 AND/OR P117B)
(a) Enter the following menus: Powertrain / Engine / Trouble Codes / Pending.
(b) Read the pending DTCs.
Result:
B -- END
A -- REPLACE ECM
25. CHECK FUEL PUMP OPERATION
(a) Check the fuel pump operation Testing and Inspection.
NG -- REPLACE FUEL PUMP (LOW PRESSURE) Removal
OK -- Continue to next step.
26. CHECK FOR FUEL LEAK (LOW PRESSURE SIDE)
(a) Check the fuel leaks.
OK:
No leakage
NG -- REPAIR OR REPLACE FUEL SYSTEM (LOW PRESSURE)
OK -- Continue to next step.
27. CHECK FUEL LINE
(a) Check the fuel line leaks or blockage.
OK:
No leakage or blockage.
NG -- REPAIR OR REPLACE FUEL LINE
OK -- CHECK AND REPLACE FUEL SYSTEM (FUEL PRESSURE REGULATOR, FUEL FILTER)
28. INSPECT A/F RELAY P0031
NG -- REPLACE A/F RELAY
OK -- REPAIR OR REPLACE HARNESS OR CONNECTOR (AIR FUEL RATIO SENSOR - A/F RELAY)
29. CHECK FUEL PRESSURE SENSOR
(a) Connect the Techstream to the DLC3.
(b) Turn the engine switch on (IG) and turn the Techstream on.
(c) Start the engine.
(d) Enter the following menus: Powertrain / Engine / Data List / Fuel Press.
(e) While revving up the engine, check that the fuel pressure fluctuates.
Standard:
Idling
3000 to 5000 kPa (30.6 to 51.0 kgf/cm2, 435 to 725 psi)
2000 rpm (No load)
7000 to 9000 kPa (71.4 to 91.8 kgf/cm2, 1016 to 1306 psi)
HINT
The A/C switch and all accessory switches should be off, and the transmission gear selector lever should be in the N or P position, and the engine should be fully warmed up.
NG -- CHECK MISFIRE COUNT
OK -- Continue to next step.
30. PERFORM ACTIVE TEST USING TECHSTREAM (CONTROL THE INJECTION WAY)
(a) Connect the Techstream to the DLC3.
(b) Start the engine and turn the Techstream on.
(c) Enter the following menus: Powertrain / Engine / Active Test / Control the Injection Way / Direct.
HINT
The A/C switch and all accessory switches should be off, and the shift lever should be in the N or P position, and the engine should be fully warmed up.
(d) Read the value Short FT #1, Long FT #1, Short FT #2, Long FT #2 and Fuel Pump Duty (D4).
Result:
D -- REPLACE ECM Removal
C -- CHECK FUEL RELIEF VALVE
B -- REPLACE FUEL PRESSURE SENSOR Removal
A -- Continue to next step.
31. PERFORM ACTIVE TEST USING TECHSTREAM (CONTROL THE INJECTION WAY)
(a) Connect the Techstream to the DLC3.
(b) Start the engine and turn the Techstream on.
(c) Enter the following menus: Powertrain / Engine / Active Test / Control the Injection Way / Direct.
HINT
The A/C switch and all accessory switches should be off, and the transmission gear selector lever should be in the N or P position, and the engine should be fully warmed up.
(d) Read the value Short FT #1, Long FT #1, Short FT #2, Long FT #2 and Fuel Pump Duty (D4).
Result:
D -- CHECK FOR INTERMITTENT PROBLEMS Check For Intermittent Problems
C -- REPLACE FUEL INJECTOR FOR DIRECT INJECTION (BANK 2) Removal
B -- REPLACE FUEL INJECTOR FOR DIRECT INJECTION (BANK 1) Removal
A -- REPLACE FUEL INJECTOR FOR DIRECT INJECTION (ALL CYLINDERS)
32. CHECK MISFIRE COUNT
(a) Connect the Techstream to the DLC3.
(b) Turn the engine switch on (IG).
(c) Turn the Techstream on.
(d) Start the engine.
(e) Enter the following menus: Powertrain / Engine / Active test / Control the Injection Way / Direct.
(f) Allow the engine to idle.
(g) Monitor all of the misfire count values that are displayed on the Techstream: Powertrain / Engine / Data List / Misfire / Cylinder #1 Misfire Count to Cylinder #6 Misfire Count.
f no misfire counts occur for any of the cylinders, perform the following procedure:
(1) Move the shift lever to D.
(2) Monitor all of the misfire rate values that are displayed on the Techstream.
Result:
B -- REPLACE FUEL INJECTOR FOR DIRECT INJECTION Removal
A -- Continue to next step.
33. INSPECT INJECTOR DRIVER
(a) Replace the injector driver with known good ones from another vehicle
NOTICE:
Do not disconnect and reconnect the connectors with the engine switch on (IG), as he injector driver (EDU) may be damaged.
(b) Connect the Techstream to the DLC3.
(c) Turn the engine switch on (IG).
(d) Turn the Techstream on.
(e) Start the engine.
(f) Clear the DTCs Reading and Clearing Diagnostic Trouble Codes.
(g) Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.
NEXT -- Continue to next step.
34. CHECK WHETHER DTC OUTPUT RECURS (DTC P0171, P0172, P0174, P0175, P1170 AND/OR P117B)
(a) Enter the following menus: Powertrain / Engine / Trouble Codes / Pending.
(b) Read the pending DTCs.
Result:
B -- END (INJECTOR DRIVER IS DEFECTIVE)
A -- Continue to next step.
35. CHECK FUEL RELIEF VALVE
(a) Connect the Techstream to the DLC3.
(b) Turn the engine switch on (IG) and turn the Techstream on.
(c) Start the engine.
(d) Enter the following menus: Powertrain / Engine / Data List / Fuel Press.
(e) Record the Fuel Press value.
(f) Turn the engine switch off.
(g) Wait for 10 seconds.
(h) Turn the engine switch on (IG) and turn the Techstream on.
(i) Enter the following menus: Powertrain / Engine / Data List / Fuel Press.
(j) Compare the Fuel Press value recorded with the engine running to the Fuel Press value currently shown on the Techstream
Result:
A -- REPLACE FUEL RELIEF VALVE
B -- REPLACE FUEL PUMP (FOR HIGH PRESSURE) Removal
36. CHECK FUEL INJECTOR FOR PORT INJECTION
(a) Check the injection volume (whether fuel volume is high or low, and whether injection pattern is poor).
NG -- REPLACE FUEL INJECTOR FOR PORT INJECTION Removal
OK -- REPLACE ECM Removal